Rotors for compressors of gas turbines or aircraft engines are for the most part constructed in such a way that air is diverted at the compressor of the engine and is conducted preferably with low loss to the inside to a consumer, in particular for cooling. As the cooling air mass flow is conducted, considerable pressure losses occur as early as when the air is diverted from the compressor drum and conducted to the disk hub on which the compressor disks are mounted. Therefore, an air mass flow of the magnitude necessary for generating sufficient cooling of the turbine is not made possible.
As a rule, apertures or bore holes are provided on the outside of the rotor so that air from the compressor drum may reach the disk hub. For example, these apertures are provided on disk vanes or flanges of the disks. A radial mass flow of compressor air from the compressor drum may enter the rotor, in particular between the disks, via these apertures. Flow losses occur since conducting the air via a bore hole into a chamber formed between the disks causes a turbulence or a swirl in the flow. A system of a free vortex and Ekman layers develops after a flow through the aperture. These flow conditions cause a great pressure drop which makes it impossible to reach the required mass flow of (0.7% to 1.5%), for example.
In order to avoid this flow pattern and the resulting pressure losses, devices, which are supposed to conduct the radial flow, are used in some engines. For example, radially directed tubes are used which are also referred to as “giggle tubes.” Using these tubes, a rigid vortex which generates only a small pressure drop may be forcibly produced. Although the required flow rate for cooling may be achieved in this way, the approach of the related art has a number of disadvantages. On the one hand, mounting these tubes poses a problem. Moreover, the weight of the rotor is a disadvantage which is increased by these tubes and the mounting device. Finally, these tubes are subject to friction wear, the so-called fretting, and are exposed to vibrations.